Halogen incandescent lamps, and particularly the lamps to which the present invention relates and which utilize an essentially cylindrical lamp bulb, may have a filament which extends essentially axially along the lamp. In the specification herein, reference will be made to two longitudinal portions or zones of the lamp, one which is close or near to the base, and the other which is remote from the base. The terms "near" and "remote" will be used, in context, with respect to the base of the lamp.
Usually, an inner current supply lead extends within the bulb to the remote end of the filament. This may also be referred to as a first current supply lead. The remote end of the bulb may have an exhaust tip, and the current supply lead can be supported in the vicinity or in the exhaust tip, see for example the referenced U.S. Pat. No. 3,497,753. This construction is complex and expensive and also results in a point-like or small area thermal loading of the glass bulb. It is difficult to manufacture such lamps, and particularly threading of the incandescent filament in a mount, and exhausting and flushing of the lamp causes difficulty.
It has been proposed--see U.S. Pat. No. 3,898,505, Danko, to bend the current supply lead at the remote end of the bulb in a circular form which closely engages at the inner wall of the glass bulb in order to ensure axial centering of the incandescent filament. This requires the current supply lead to be bent into the aforementioned circular arrangement, that is, in three dimensions. Three-dimensional bending causes relatively high manufacturing and assembly costs. Adjustment of the current supply lead with respect to the overall filament mount is difficult, particularly if very precise centering of the filament with respect to the lamp axis is required.